Hydraulic pump-turbine

ABSTRACT

A hydraulic pump-turbine in which the blades of the guiding apparatus during turbine operation are arranged in a holder which during pump operation rotates at a higher speed than the number of revolutions of the main runner with the help of an independent electric motor.

United States Patent 11 1 Kazachkov et a1.

[ Sept. 11, 1973 HYDRAULIC PUMP-TURBINE Inventors: Lev Yakovlevich Kazachkov; Jury Abramovich Lesokhin, both of Leningrad, U,S.S.R.

Filed: Aug. 16, 1971 App]. No.: 172,217

Related US. Application Data Continuation of Ser. No. 836,434, June 25, 1969, abandoned.

Foreign Application Priority Data July 8, 1968 U.S.S.R 1254747 U.S. c1 415/69, 415/1, 415/500,

1m. (:1. ..-F01d--1/24, F04d 25/16 Field of Search 415/61, 500, 68, 415/69, 122, 147, 21, 22; 417/236, 237

References Cited UNITED STATES PATENTS 2/1908 Riggs ..415/68 910,164 l/1909 Berg 415/68 1,919,376 7/1933 Moody 415/500 2,434,678 l/1948- Szczeniowski.. 415/122 3,372,645 3/1968 Willi 415/500 2,671,635 3/1954 Willi 415/500 3,356,035 12/1967 Sproule 415/500 X FOREIGN PATENTS OR APPLICATIONS 576,498 4/1946 Great Britain 415/122 579,780 8/1946 Great Britain 415/68 934,364 8/1963 Great Britain 415/500 U.S;S.R 415/500 Primary Examiner-Wil1iam L. Freeh Assistant Examiner-John T. Winburn Attorney-Waters, Roditi, Schwartz & Nissen [57] ABSTRACT I A hydraulic pump-turbine in which the blades of the guiding apparatus during turbine operation are arranged in a holder which during pump operation rotates at a higher speed than the number of revolutions of the main runner with the help of an independent electric motor.

10 Claims, 3 Drawing Figures PATENTEDSEPHIQB I s 758 225 SHEET 1 OF 2 FIG! PATENTEDSEP! 1 I373 SHEET 2 [IF 2 HYDRAULIC PUMP-TURBINE The present invention relates to hydraulic machines, and more specifically to hydraulic pump-turbines wherein the blades of the gate apparatus are mounted with a capability of their power rotation for pump operation, so as to perform the function of an additional pressure stage.

In prior art hydraulic pump-turbines, the blades of the gate apparatus are mounted in a holder that can be selectively joined with the stationary base of the hydraulic pump-turbine for turbine operation, or it can be joined with another blade holder permanently connected to a motor-generator for pump operation. In the latter case both blade holders are positively rotated in the same direction and at equal speeds (see, for exam ple, the USSR Authors Certificate No. 200506, cl. 88a, 1965).

When the prior art pump-turbines are employed under conditions of relatively low pressure heads, there occurs cavitation which causes intense erosion of the blades and unstable operation of the machine.

An object of the invention is to reduce cavitation in such machines under relatively low pressure head conditions.

The principal object of the invention is'to provide a pump-turbine with two blade holders, one of which (the first one) is permanently connected with a motorgenerator, and the other holderv (the second one) is mounted with capability of being selectively joined to the stationary base of the pump-turbine, or to a drive that will allow redistribution of loads between the two blade holders by reducing the load on the first holder, and increasing the load on the second blade holder.

According to the invention, this is achieved by providing the second blade holder with a drive. that can develop a speed exceeding that of the first holder.

The pump-turbine according to the invention permits cavitation to be substantially reduced, as compared to the prior art machine using the same pressure head, by reducing the speed of the first holder so as to keep it below the cavitational conditions, and at the same time raising the speed of rotation of the second holder of which the cavitation effects are less characteristic since it performs the function of the second stage of the pump. a

The required difference of speeds between the two holders can be by using an independent drive with the second holder, whose speed of rotation exceeds that of the motor-generator.

Alternatively the second blade holder can be driven from the motor-generator through a multiplicator or a torque converter.

Cavitation effects are considerably reduced when the speed of the second blade holder is raised by at least 3 percent with respect to the speed of the first holder. However, the most effective reduction of cavitation is observed when the speed of the second holder is increased by l-20 percent.

Given below is a detailed-description of a preferred embodiment of the hydraulic pump-turbine made according to the invention, with references to the appended drawings, wherein:

FIG. 1 shows a part of the pump-turbine, in longitudius] section;

FIG. 2 is a section taken on line IIII in FIG. 1, the

tion; and

FIG. 3 is section III-Ill in FIG. 1, the position of the blades corresponding to pump operation.

The hydraulic pump-turbine comprises holder 1 of blades 2 with top blade rim 3 and bottom rim 4. Blades 2 are welded to these rims. Holder 1 is mounted on shaft 5 by bolts (not shown in the drawings). Shaft 5 is connected to the output shaft 29 of a motor-generator 30. Shaft 5 is disposed inside shaft 6 which is connected with the drive of a hollow second holder 7 of blades 8. Employed as the drive of the second holder 7 is an electric motor 31 coupled to the shaft, blades 8 are mounted in the second holder 7 by means of journals 9 connected through gears 10 to a gear ring 11 which can be moved by servo-motor 12 whose construction and operation is entirely conventional and well known to those skilled in the art. Servo-motor l2, gear ring 1 l, and gears 10 are located inside holder 7. Blades 8 are located between blades 2 and columns 13 of the stationary base 14 of the pump-turbine. Columns 13 are surrounded by a volute chamber 15. Disposed under blades 2 is channel 16 communicating the pumpturbine with the tail water of the water storaging power station (the tail water and the power station are not shown in the drawings).

In the case of turbine operation, fluid comes to the pump-turbine from the volute chamber 15. Mounted on top of the second holder 7 is cover 17 of the pumpturbine which cover rests on the stationary base 14.

Shaft 5 is fixed in bearing 18 mounted on the second holder 7, and shaft6 is fixed in bearing 19 mounted on cover 17.

Disposed on the periphery of shaft 6 are splines 20, and positioned concentrically with the latter are splines 21 which are joined to the stationary base 14 by means of a cylindrical part 22. Located in the annular gap between the cylindrical part 22 and shaft 6 is servo-motor 23 whose construction is conventional and whose piston rod carries a toothed stop 24 the teeth of the latter being capable of simultaneously engaging splines 20 and splines 21.

Oil is supplied to servo-motor 12 from an annular collector 25 encircling shaft 6 and communicating with said servo-motors via pipes 26.

The clearance between the bottom parts of blades 8 and the stationary base 14 is sealed by ring 27 pressed against blades 8 with the aid of conventional servomotors 28.

For turbine operation the toothed stop 24 is engaged with splines 20 and 21, thus the second holder 7 of blades 8 are connected with the stationary base 14. Water from the volute chamber 15 arrives at blades 2 of the first holder 1 after it passes through blades 8 of the second holder 7 which functions as the gate apparatus. Holder 1 is then rotated, the direction of which is shown by the arrow in FIG. 2. This motion is communicated to the motor-generator through shaft 5. Water arrives then at channel 16. I

To convert the pump-turbine to pump operation the toothed stop 24 is disengaged from splines 20 and 21, the connection between the second holder 7 and the stationary base 14 is removed, and positive rotation being communicated to this holder from its drive 2 and so improve the cavitational properties of the pump-turbine. The difference between the speeds of the holders is 15 percent.

Water through channel 16 passes to blades 2 of the first holder 1, and then to blades 8 of the second holder 7, and is then drawn away from the pump-turbine through the volute chamber 15.

In the case of pump operation the seal ring 27 is retracted from blades 8 so as to avoid friction.

Employed as the drive of holder 7 of blades 8 instead of said electric motor may be a multiplicator or a torque converter coupled to the motor-generator through shaft of holder 1 of blades 2.

We claim:

1. A hydraulic pump-turbine comprising: a stationary base; a first blade holder mounted in said base; a shaft upon which said first blade holder is mounted; a motorgenerator including a rotor drivingly coupled to said shaft; a second holder'with adjustable blades, said second holder being mounted in said base, the blades of said second holder being positioned upstream of the blades of said first holder along the stream of fluid in turbine operation; a drive for said second holder for imparting to the second holder a speed exceeding the speed of said firstholder to reduce cavitation effects during operation as a pump; and means for selective connection of said second holder with said stationary base during turbine operation or said drive during pump operation.

2. A pump-turbine according to claim 1, wherein the drive of the second holder is independent of the drive of said motorgenerator.

3. A pump-turbine according to claim 1, wherein said drive of said second holder includes means for imparting to the latter holder a speed exceeding the speed of the first holder by at least 3 percent.

4. A pump-turbine according to claim 1, wherein said drive of said second holder includes means for imparting to the latter holder a speed exceeding the speed of the first holder by 10-20 percent.

5. A pump-turbine according to claim 1, wherein said drive for said second holder includes a second shaft encircling the first shaft of the first blade holder.

6. A pump-turbine according to claim 5 wherein said means for selective connection of the second holder with the base or drive comprises a displaceable element having one position in which said element couples said second shaft to said base and a second position in which the second shaft and base are uncoupled.

7. A pump-turbine according to claim 1 comprising means rotatably supporting each of the adjustable blades in the second holder and means for rotating the adjustable blades of the second holder around their respective rotation axes.

8. A pump-turbine according to claim 7 wherein said means for rotating the adjustable blades comprises a motor and means coupling the motor with each of the adjustable blades to rotate the latter in common.

9. A pump-turbine according to claim 1 wherein for turbine operation said second holder is connected to said base by the means therefor and said rotor which is coupled to the shaft serves as a generator rotor.

10. A pump-turbine according to claim 1 wherein for pump operation said second holder is connected to said drive by the means therefor and said rotor which is coupled to the 'shaft serves as a motor rotor. 

1. A hydraulic pump-turbine comprising: a stationary base; a first blade holder mounted in said base; a shaft upon which said first blade holder is mounted; a motor-generator including a rotor drivingly coupled to said shaft; a second holder with adjustable blades, said second holder being mounted in said base, the blades of said second holder being positioned upstream of the blades of said first holder along the stream of fluid in turbine operation; a drive for said second holder for imparting to the second holder a speed exceeding the speed of said first holder to reduce cavitation effects during operation as a pump; and means for selective connection of said second holder with said stationary base during turbine operation or said drive during pump operation.
 2. A pump-turbine according to claim 1, wherein the drive of the second holder is independent of the drive of said motor-generator.
 3. A pump-turbine according to claim 1, wherein said drive of said second holder includes means for imparting to the latter holder a speed exceeding the speed of the first holder by at least 3 percent.
 4. A pump-turbine according to claim 1, wherein said drive of said second holder includes means for imparting to the latter holder a speed exceeding the speed of the first holder by 10-20 percent.
 5. A pump-turbine according to claim 1, wherein said drive for said second holder includes a second shaft encircling the first shaft of the first blade holder.
 6. A pump-turbine according to claim 5 wherein said means for selective connection of the second holder with the base or drive comprises a displaceable element having one position in which said element couples said second shaft to said base and a second position in which the second shaft and base are uncoupled.
 7. A pump-turbine according to claim 1 comprising means rotatably supporting each of the adjustable blades in the second holder and means for rotating the adjustable blades of the second holder around their respective rotation axes.
 8. A pump-turbine according to claim 7 wherein said means for rotating the adjustable blades comprises a motor and means coupling the motor with each of the adjustable blades to rotate the latter in common.
 9. A pump-turbine according to claim 1 wherein for turbine operation said second holder is connected to said base by the means therefor and said rotor which is coupled to the shaft serves as a generator rotor.
 10. A pump-turbine according to claim 1 wherein for pump operation said second holder is connected to said drive by the means therefor and said rotor which is coupled to the shaft serves as a motor rotor. 